The entire disclosure of Japanese Patent Application No. 2000-128853 filed on Apr. 28, 2000 including specification, claims, drawings and summary is incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to an inking apparatus for a printing press, and, more particularly, to an inking apparatus for a printing press capable of performing rainbow printing.
2. Description of the Related Art
An example of such printing press is a four-color double-sided simultaneous offset printing press as shown in FIG. 3.
In a printing unit 1 of the main unit, a rubber impression cylinder 2 having a paper gripping apparatus and a rubber cylinder 3 having no paper gripping apparatus are supported substantially horizontally such that the circumferential surfaces of the cylinders 1 and 2 are in contact with each other.
Four plate cylinders 4 are disposed along the circumferential surface of the rubber impression cylinder 2; and four plate cylinders 5 are disposed along the circumferential surface of the rubber cylinder 3. Inking units 6 and 7 are movably disposed such that the inking units 6 and 7 can approach and separate from the plate cylinders 4 and 5, respectively. The inking units 6 and 7 can supply ink and water to the plate cylinders 4 and 5 in a state in which the inking units 6 and 7 are in contact with the plate cylinders 4 and 5.
Meanwhile, a delivery cylinder 9 of a delivery unit 8 is disposed below the rubber impression cylinder 2. A chain 10 is disposed on the left side of the delivery cylinder 9 in FIG. 3, such that the chain 10 does not cross a space below the position at which the circumferential surface of the rubber impression cylinder 2 is in close proximity with that of the rubber cylinder 3.
Further, transfer cylinders 12 to 15 each having a paper gripping apparatus are provided in order to transfer paper from a register 11 to the rubber impression cylinder 2; and a transfer cylinder 16 having a paper gripping apparatus is provided in order to transfer paper from the rubber impression cylinder 2 to the delivery cylinder 9. In FIG. 3, reference numeral 17 denotes a feeder unit.
Accordingly, a sheet of paper fed from the feeder unit 17 and positioned by the register 11 is conveyed along a path indicated by arrows in FIG. 3; i.e., is conveyed along the circumferential surfaces of the transfer cylinders 12 to 15, the circumferential surface of the rubber impression cylinder 2, the circumferential surface of the transfer cylinder 16, and the circumferential surface of the delivery cylinder 9, in this sequence. When the sheet of paper passes through the contact point between the rubber impression cylinder 2 and the rubber cylinder 3 from the upper side to the lower side of the contact point, the opposite faces of the sheet of paper undergo printing simultaneously.
As shown in FIG. 4, in each of the inking units 6 and 7, an upper set consisting of an ink fountain roller 21a and an ink ductor roller 22a and a lower set consisting of an ink fountain roller 21b and an ink ductor roller 22b are provided. The ink fountain rollers 21a and 21b are disposed and rotatably supported in respective ink fountain apparatuses 20a and 20b. The ink ductor rollers 22a and 22b are supported to be rotatable in close proximity with the ink fountain rollers 21a and 21b and be swingable. Ink is transferred from these upper and lower rollers to an ink mixing (distribution) roller 23 and then transferred to an ink form roller 25 via an ink roller group 24 including an ink distribution roller and an ink oscillating roller. In FIG. 4, reference numeral 26 denotes an ink roller group for another color.
When so-called rainbow printing; i.e., printing adjacent areas in different colors while shading off the colors at the boundary portion therebetween, is to be performed, inks of different colors are charged in the two ink fountain apparatuses 20a and 20b, and printing is then performed. Since mixing of colors does not occur in the ink fountain apparatuses, quality of printing products is improved, and a larger amount of ink can be stored in the ink fountains in order to improve productivity.
However, in the above-described conventional inking apparatus, within each of the inking units 6 and 7, the upper and lower ink fountain apparatuses 20a and 20b are disposed radially with respect to the ink mixing roller 23 with the same number of rollers being interposed for each ink fountain, whereby ink stored in each ink fountain is transferred to the ink mixing roller 23.
Therefore, when the ink ductor rollers 22a and 22b are exchanged in order to cope with a change in printing specification of rainbow printing or the like, an operator must move the inking units 6 and 7 or must move between the opposite sides of the inking units 6 and 7, because the ink ductor rollers 22a and 22b differ from each other in removal direction (see arrows in FIG. 4). In some cases, the ink from roller 25 also must be removed temporarily. Therefore, a very long work time is needed to complete the exchange work.
Further, since a sufficient work space is not present on the upper side of the lower ink fountain apparatus 20b, attachment of the ink ductor roller 22b involves lifting the ink ductor roller 22b from below, and removal of the ink ductor roller 22b involves supporting the ink ductor roller 22b from below. These operations are heavy labor for the operator, resulting in imposition of a large workload on the operator.
Furthermore, in each of the inking unit 6 and 7, the operator must perform the replacement work within a narrow work space between the ink roller group 24 and the ink roller group 26 for another color disposed above the ink roller group 24. Therefore, the operator encounters difficulty in performing the work, and a large workload is imposed on the operator. In addition to the above-described problem, the conventional inking apparatus involves various other problems.
In view of the foregoing, an object of the present invention is to provide an inking apparatus for a printing press, which can shorten operator""s work time and lessen workload imposed on the operator.
In order to achieve the above-described object, the present invention provides an inking apparatus for a printing press comprising: upper and lower fountain rollers disposed and rotatably supported in respective ink fountain apparatuses; upper and lower ductor rollers supported so as to be rotatable in close proximity with the fountain rollers; and an ink mixing roller which is the farthest upstream ink roller to which ink is transferred from the upper and lower ductor rollers, wherein one of the ductor rollers is located immediately adjacent the ink mixing roller and at least one intermediate roller is provided between the ink mixing roller and the other ductor roller of the upper ductor roller and the lower ductor roller.
Since attachment and removal of the upper and lower ink ductor rollers can be performed from the side of the ink fountain apparatuses where a large work space is provided, operator""s work time can be shortened, and the workload imposed on the operator can be lessened.
Preferably, the upper and lower ductor rollers are supported so as to be removable upward. In this case, the workload imposed on the operator can be decreased further.
Preferably, opposite axial end portions of each of the upper and lower ductor rollers are supported, via split holders, on arms fixed to opposite end portions of a swing support shaft; and upper halves of the split holders can be swung upward to open to thereby enable upward removal of the upper and lower ductor rollers.
Preferably, the at least one intermediate roller is provided between the lower ductor roller and the ink mixing roller.
Preferably, the at least one intermediate roller consists of first and second intermediate rollers.